Quantcast I can't get the Vs ! can someone take a look at it? Text - Physics Forums Library

PDA

View Full Version : I can't get the Vs ! can someone take a look at it?


325ci
Sep4-08, 11:36 AM
Can someone help me to find the Vx please?


http://i358.photobucket.com/albums/oo23/au325ci/untitled.jpg

Defennder
Sep4-08, 11:43 AM
Well, what have you tried so far? Use your favorite method of solving linear circuits here. I'll go for nodal analysis Start by writing equations of current flow into and out of designated nodes, then solve them.

Note that the given conditions effectively say that 35W = VI where V is the votage across the 7A current source, and I is the current source through it.

325ci
Sep4-08, 11:53 AM
Yea I get tHe currents and voltage across the resistor on the below loops but when I go up to Vx I get 2 unknown 1 equation so can't solve it gotta find another equation

CEL
Sep4-08, 05:34 PM
Yea I get tHe currents and voltage across the resistor on the below loops but when I go up to Vx I get 2 unknown 1 equation so can't solve it gotta find another equation

The only unknown is Vx.

Defennder
Sep4-08, 09:48 PM
Did you use what is given in the text of the question to get the node voltage at the point above the 7A current source? Also note that you will get two unknown node voltages, the one to the right of Vx (call this V1) and Vx itself. Note that once you have the node voltage of the point above the 7A source you can solve for V1. Then, writing a nodal equation for V1, you can easily find Vx.

325ci
Sep5-08, 08:47 AM
well i got it thanks yall